It has been found that diagnostic medical imaging equipment, such as magnetic resonance imaging (MRI) devices, are sensitive to mechanical or natural vibrations from external sources. The vibrations are generally transmitted to the device through the base upon which the imaging device is situated.
Numerous external sources of vibration have been identified. Generally, diagnostic equipment is located in hospitals or other healthcare sites situated near major roads or highways and developed areas wherein road traffic comprising automobiles, buses, trucks and even trains have been noted for causing harmful vibrations. Other such vibration producing sources within healthcare sites include but are not limited to mechanical and hydraulic elevators, heating ventilating and air conditioning systems (HVAC), air compressors, extractor fans and water and vacuum pumps.
Generally, the vibrations transmitted to diagnostic equipment result in degraded and reduced quality images at least in the form of snowy, blurred or replicated images. Since the preferred magnet is an open type and not the tunnel or sewer pipe, it is theorized that the North and South Pole relationship actually changes. This causes a fluctuation in the magnetic field purity. This purity is specified in PPM (part per million). The preferred MRI device of the present invention has a specification of 3 PPM and any disturbance greater than about 0.03 PPM will cause image artifacts which are recorded by the MRI Imager.
Prior to the present invention, there have been numerous attempts to reduce vibrations, noise, impulses or shocks both to and from various machines.
U.S. Pat. No. 2,126,660 to Pogue relates to apparatus reportedly used for preventing the vibrations of an engine or machine from being transmitted to the building or structure within which or upon which the engine or machine is installed, and particularly, anti-vibration-supporting apparatus of the type that employ springs for taking up or absorbing the vibrations of the engine or machine.
U.S. Pat. No. 2,605,066 to Brown relates to machinery supports for heavy, impact generating machines, such as forging machines, wherein the vibration from the machines to surrounding surfaces is limited.
U.S. Pat. No. 3,499,255 to Sweeney et al. relates to a vibration isolation floor construction for supporting vibration sensitive and vibration producing machines, equipment and the like. The floors comprise pads of glass fiber material which are formed so as to maintain constant natural frequencies under variations in loading. In particular, the floor constructions are constructed and loaded in accordance with fabricated isolation pads. In addition, the floor constructions can be fabricated in accordance with a formula which has been established to provide the above-mentioned advantages.
U.S. Pat. No. 4,436,274 to Kramer relates to a laminated vibration isolation pad comprising first or top rigid layer of ultra-high molecular weight polyethylene material, a second layer of vulcanized elastomeric material with an additional third or bottom layer of spaced resilient vulcanized elastomeric projections. The laminated vibration isolation pad is fabricated as a unitary structure with the polyethylene layer bonded or fused to the rubber layer while being formed.
U.S. Pat. No. 5,016,638 to Hsieh relates to a medical NMR scanner adapted to be supported on the floor of a building or other structure by vibration limiting supports. The scanner includes a frame defining a patient-receiving space adapted to receive a human body. It also includes a pair of opposed polar regions aligned on a polar axis. The polar regions are disposed on opposite sides of the patient-receiving space. Structure is provided in each of the polar regions for producing a magnetic field within the patient-receiving space. Attenuators, positioned intermediate the frame and the building floor, are provided for reportedly attenuating transmission of vibrations from the floor to the magnetic field producing structure in order to reduce scanner image degradation.
U.S. Pat. No. 5,573,220 to Whittaker et al. relates to a reportedly vibration absorbing and leveling machinery foundation mount and a method for tuning the same, the mount consisting of a rigid horizontal platform having a plurality of vibration absorbing legs. A leveler is mounted in the central region of the platform having a vertically adjustable riser, and the legs are formed by pockets housing a composite vibration absorbing material extending below the platform and engaging the surface upon which the machinery mount is supported which may be tuned to most effectively absorb the vibration to which the mount is subjected.